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Biomedical subjects

K McHugh

Publications and source records attributed to K McHugh.

At least 19 recordsLinked to original sources
PubMed1998

The role of micturating cystourethrography in antenatally detected mild hydronephrosis.

BACKGROUND: The postnatal imaging of infants with antenatally detected mild hydronephrosis remains controversial. OBJECTIVE: Our aim was to establish the role and timing of micturating cystourethrography (MCUG) in mild hydronephrosis. MATERIALS AND METHODS: We performed a retrospective study of 61 infants (122 kidneys) referred with an antenatal diagnosis of hydronephrosis who showed persistent postnatal dilatation. All had follow-up postnatal ultrasound (US) and MCUG performed. The degree of dilatation at each follow-up scan was recorded. RESULTS: Of the 122 kidneys, 65 showed mild hydronephrosis. A substantial proportion of these (21.5%) demonstrated reflux. Serial US of these infants showed that the 6-week scan was the most informative and that any changes that warranted further investigation had occurred by this time. CONCLUSION: We recommend that all infants with mild hydronephrosis should undergo MCUG. MCUG need not be delayed until 3 months but could be performed following a 6-week US scan.

Female↗
PubMed1998

The role of radiology in children with anorectal anomalies; with particular emphasis on MRI.

Anorectal anomalies have a reported incidence of between 1 per 1000 and 1 per 9630 live births. The international classification subdivides anorectal malformations into high, intermediate, low and miscellaneous deformities with emphasis on the sex of the child. The classification is based on where the rectum terminates in relation to the levator ani muscles above the levator is termed a high (supralevator) lesion, at the level of the levator intermediate, and below is a low or translevator anomaly. A modified classification has recently been proposed by Pena based on his anatomic observations during posterior sagittal anorectoplasty-the terms high, intermediate and low lesions continue to be used but with slightly different connotations. Approximately 50% of all patients with anorectal anomalies have associated other congenital lesions. These lesions necessitate a variety of radiological investigations which will be outlined briefly. The pertinent muscular anatomy of the pelvic floor and recent advances in surgical techniques will be discussed. The particular role of MRI in the evaluation of the pre-operative newborn or infant prior to definitive pull-through repair surgery and the post-operative, older, paediatric patient with continuing problems will be reviewed. Reference to the other radiological options, and their usefulness, in the evaluation of anorectal malformations will be made throughout the text.

Anal Canal↗
PubMed1997

Factors influencing patient loyalty to dentist and dental practice.

OBJECTIVE: To establish the factors considered by adult regular dental attenders to be the most important in choosing to stay with a particular dentist or practice. DESIGN: An anonymous questionnaire to be completed by patients. SETTING: General dental practices in England and Wales with a significant proportion of patients seen under some form of private contract. SUBJECTS AND METHODS: 13 practices in England and Wales were selected to represent a regional cross-section of the country. Up to 100 successive patients visiting each practice during the summer of 1995 were invited to complete the questionnaire. 1003 questionnaires were returned. RESULTS: Notwithstanding regional, gender and socio-economic status related differences the most important factors were 'care and attention' rated as very important by 90% of respondents, 'pain control, 'dentist puts you at ease ', 'safety conscious' all rated as very important by 79-82% of respondents, and 'explanation of treatments' rated as very important by 73% of respondents. The importance attached to the dentist being 'safety conscious' suggests a change in emphasis from earlier studies. CONCLUSIONS: The factors rated most important reflect the dentist's behaviour and personal skills in devoting time and attention to the patient.

Adult↗
PubMed1997

The mechanism of altered neural function in a rat model of acute colitis.

BACKGROUND & AIMS: Distal colitis induced in rats by trinitrobenzene sulfonic acid (TNBS) causes a suppression of [3H]noradrenaline release from the myenteric plexus, of inflamed distal colon, as well as in noninflamed regions of colon and ileum. The aim of this study was to explore the mechanisms underlying these neural changes in TNBS colitis. METHODS: Colitis was induced by intrarectal administration of TNBS, and the animals were killed on day 5. Inflammation was assessed by measuring myeloperoxidase (MPO) activity, and noradrenaline release was measured as 3H release from rats myenteric plexus preparations preloaded with [3H]noradrenaline. These end points were examined: (1) after administration of the locally active steroid budesonide; (2) in congenitally athymic rats; and (3) in rats treated with the interleukin 1 receptor antagonist (IL-1ra) to interleukin 1 beta. RESULTS: In colitis, both topical budesonide and systemic IL-1ra treatments attenuated the suppression of KCl-evoked 3H release from longitudinal muscle myenteric plexus in both inflamed and noninflamed segments. However, neither of these treatments altered MPO activity. A similar suppression of [3H]noradrenaline release was observed in athymic rats after TNBS, although there was a substantially greater increase in MPO activity compared with euthymic rats with colitis. CONCLUSIONS: TNBS-induced colitis alters myenteric nerve function at inflamed and noninflamed sites via a steroid-sensitive and interleukin 1-mediated process that does not require T lymphocytes.

Acute Disease↗
PubMed1997

Molecular marker for development of interstitial cystitis in rat model: isoactin gene expression.

PURPOSE: To determine whether the differential expression of bladder smooth muscle isoactin can be used as a molecular marker for the development of interstitial cystitis (IC). METHODS: Three groups of five female Sprague-Dawley rats each underwent urethral catheterization and intravesical instillation of 0.5 ml. of 0.4N HCl. One group was sacrificed one, two and four weeks after the application of HCl, and their bladders harvested for histologic examination and evaluation using Northern blot analysis of bladder smooth muscle isoactins. Five control animals were sacrificed and their bladders harvested to establish isoactin gene expression of bladder smooth muscle in the normal state. The bladders of the rats in each group were excised, immediately frozen in liquid nitrogen, pooled, then stored -70 degrees C until needed for RNA isolation. Isoactin cDNA probes have been developed, therefore isoactin specific cDNA insert fragments were isolated and insert DNA was purified by gel electrophoresis. Total cellular RNA was isolated from 1.0 gm. of bladder smooth muscle from each group. After spectrophotometric quantification, Northern Blot analysis was performed using 2% agarose-formaldehyde gels and Biotrans nylon membranes. Two complete Northern Blot series were run on a single gel and blotted to a single membrane to eliminate gel and blotting discrepancies. RESULTS: Microscopic histologic analysis revealed detrusor mastocystosis and eosinophilia as has been noted in humans with chronic interstitial cystitis. Two weeks after the intravesical application of hydrochloric acid, the relative expression of gamma-smooth muscle isoactin was noted to increase by 1.7-fold, while alpha-smooth muscle isoactin expression increased by a factor of 9. These effects were seen to stabilize four weeks after acid application. CONCLUSIONS: The intravesical application of dilute HCl in rats results in a histologic appearance which mimics that seen in humans with interstitial cystitis. The appearance of detrusor mastocytosis and eosinophilia was accompanied by a relative decrease in the expression of gamma- and a relative increase in alpha-smooth muscle isoactin gene expression. This pattern of smooth muscle isoactin expression is consistent with a more immature and possibly synthetic smooth muscle phenotype, which may be responsible for the clinical presentation of those with IC. Northern blot analysis of bladder smooth muscle cells may serve as an effective marker for the development of interstitial cystitis in humans.

Actins↗
PubMed1996

MRI findings in children with neurofibromatosis type 1: a prospective study.

To determine the frequency and nature of MRI lesions in children with neurofibromatosis type I (NF1), 50 patients aged 8 to 16 years were evaluated prospectively with cranial MRI. Forty-one children were asymptomatic with respect to central nervous system pathology, and 50% were macrocephalic. Sixteen patients (32%) had normal MRI examinations. Thirty-two patients (64%) had high intensity lesions on T2-weighted images and 16 patients (32%) had hyperintense lesions on T1-weighted images. Seven patients (14%) had ventricular dilatation (associated with increased intracranial pressure in 2) and 11 patients (22%) had optic pathway lesions (optic glioma in 7). MRI was superior to CT in differentiating optic sheath thickening and optic nerve tortuosity from optic glioma in four patients. An intracranial tumour (ependymoma) and sphenoid wing dysplasia were evident in individual patients. Findings previously unreported in NF1 included an aqueductal web resulting in hydrocephalus, intraocular neurofibroma resulting in retinal detachment, and asymptomatic enlargement of the septum pellucidum. T1 and T2 signal abnormalities in isolation were not associated with neurological deficits or the occurrence of macrocephaly, and all lesions that required intervention were suspected clinically. Macrocephaly in the absence of increased intracranial pressure or accelerated head growth is not an indication for neuroimaging in children with NF1. However, the majority of children (68%) had disease-specific abnormalities and thus MRI may provide a useful adjunct to clinical evaluation in the diagnosis of equivocal cases.

Brain↗
PubMed1996

Previous inflammation alters the response of the rat colon to stress.

BACKGROUND & AIMS: Patients with inflammatory bowel disease have symptoms of irritable bowel syndrome (IBS) with a higher than expected prevalence. Stress is an important factor in the pathogenesis of IBS. Thus, previous inflammation may predispose to IBS by rendering the bowel more susceptible to the impact of stress. The aim of this study was to examine the effect of previous colitis on stress-induced responses in rats. METHODS: Acute colitis was induced in rats by intrarectal administration of trinitrobenzene sulfonic acid (TNBS), and the rats were allowed to recover for 6 weeks before application of mild restraint stress for 3 consecutive days. In vitro measurements included myeloperoxidase activity, plasma corticosterone levels, interleukin 1 beta messenger RNA expression, and [3H]noradrenaline release from the myenteric plexus. RESULTS: Six weeks after administration of TNBS, stress caused a significant increase in myeloperoxidase activity in TNBS-treated rats but not in stressed controls; plasma corticosterone responses were similar. Stress also caused an exaggerated and significant suppression of [3H]noradrenaline release in TNBS-treated stressed rats compared with stressed controls. This was accompanied by a significant decrease in interleukin 1 beta messenger RNA expression in the colon. CONCLUSIONS: Previous colitis rendered the colon more susceptible to effects of stress on enteric nerve function and also increased some parameters of inflammation in response to stress.

Animals↗
PubMed1995

Interleukin-4 induces expression of the integrin alpha v beta 3 via transactivation of the beta 3 gene.

Osteoclastic bone resorption is dependent upon cell-matrix recognition. This process is mediated by the integrin alpha v beta 3 whose expression is enhanced, in avian osteoclast precursors, by bone-seeking steroids. The purpose of this study was to determine if bone-modulating cytokines impact on alpha v beta 3 expression by mouse marrow macrophages (BMMs), known to differentiate into osteoclasts. Of the cytokines tested. Interleukin-4 (IL-4) is most effective in increasing beta 3 mRNA levels by a mechanism involving transactivation of the beta 3 gene. Moreover, IL-4 augmented beta 3 mRNA is mirrored by plasma membrane appearance of alpha v beta 3. As IL-4 induces beta 3 and not alpha v mRNA, the beta 3 chain appears to regulate surface expression of the heterodimer. The functional significance of IL-4-induced alpha v beta 3 is underscored by the fact that, while attachment to fibronectin is unaltered, treatment of BMMs with the cytokine enhances alpha v beta 3-mediated binding to vitronectin 5-fold. Expression of this heterodimer by BMMs driven along a non-osteoclastic lineage suggests alpha v beta 3 may play a role in the inflammatory response of macrophages.

Animals↗
PubMed1995

Experimental colitis alters myenteric nerve function at inflamed and noninflamed sites in the rat.

BACKGROUND & AIMS: Studies in inflammatory bowel disease have shown extensive structural abnormalities in the enteric nervous system of inflamed and noninflamed gut; however, functional correlates are lacking. The aim of this study was to determine the effect of colitis on myenteric nerve function at inflamed and noninflamed sites in rat intestine. METHODS: Tritiated noradrenaline release was measured from longitudinal muscle myenteric plexus preparations from the distal and transverse colon and terminal ileum of rats with colitis induced by trinitrobenzene sulfonic acid or Trichinella spiralis larvae. RESULTS: As characterized by myeloperoxidase activity and histology, both models induced inflammation restricted to the distal colon. In distal colon in trinitrobenzene sulfonic acid colitis, KCl- or electrical field stimulation-evoked 3H release was suppressed by 56% and 60%, respectively; in T. spiralis-infected rats, the KCl-evoked release was suppressed by 58%. 3H release was also suppressed by similar magnitudes in noninflamed transverse colon and terminal ileum of each model. CONCLUSIONS: Experimental distal colitis alters myenteric nerve function in inflamed distal colon and noninflamed gut regions. These changes are independent of the manner in which colitis is induced and provide a basis for the extensive disruption of physiological function observed in inflammatory bowel disease.

Adrenergic Fibers↗
PubMed1995

The post-angiocardiography urogram in children: should it be abandoned?

This study examines the value of the urogram radiograph taken after angiocardiography, in children with suspected congenital heart disease, to screen for co-existent urinary tract abnormalities. A retrospective audit of post-angiocardiography urograms over a three year period 1990 to 1993 is presented. 184 urograms obtained in 166 children were reviewed (86 males; mean age 18.1 months). Twenty-five urograms (13.6%) were obtained in cases where the urinary tract had previously been investigated. These urograms contributed no additional information. Image quality was suboptimal in 62 examinations (33.7%), due to gas, faeces or poor opacification, and two lesions were undetected on suboptimal radiographs. Urinary tract abnormalities were detected in 17 patients (10.2%). These lesions were also detectable at sonography. We suggest that routine post-angiocardiography urograms can be abandoned in favour of sonographic screening of the urinary tract in children with congenital heart disease.

Adolescent↗
PubMed1995

CT of staphylococcal anterior mediastinal abscess in an infant.

A 6-week-old girl presented with bronchiolitis secondary to respiratory syncytial virus. Eight days after admission she developed a Staphylococcus aureus infection at a previous intravenous cannula site. Despite antibiotic therapy this led to an anterior mediastinal staphylococcal abscess, which was drained surgically and the patient recovered. Mediastinal abscesses are rare in children: haematogenous spread of infection is an unusual aetiological factor and we believe this to be the first case reported due to an infected cannula site.

Abscess↗
PubMed1995

Pre-operative MRI of anorectal anomalies in the newborn period.

Nine infants (six boys, three girls) with anorectal anomalies were examined in the immediate newborn period, prior to corrective surgery, with MRI. Three high, one intermediate and five low anomalies were found at MRI - one patient with a low lesion was subsequently found at surgery 2 months later to have a high anorectal anomaly. This infant had passed meconium per urethram soon after the MRI study, prompting the need for a protective colostomy and stressing the importance of a thorough clinical examination of babies with anorectal malformations. The MRI results and findings at surgery were in agreement in all other patients (n = 8). Hydronephrosis was evident in two and renal agenesis in one patient. Sacrococcygeal hypoplasia was found in two and two hemivertebrae in one infant. No spinal cord lesion was identified. One fistula was evident on MRI but four were later found at surgery. Uniformly hyperintense T 1 signal meconium was seen in all nine newborns, allowing for easy differentiation of rectal contents from rectal wall and the adjacent musculature. MRI can provide useful information regarding the development of the puborectal and external anal sphincter muscles, can help guide the pull-through procedure and help predict future continence pre-operatively in the newborn period.

Anal Canal↗